Rotary compressor

ABSTRACT

A rotary compressor comprising a cylinder, a vane slidably mounted in the cylindrical wall of the cylinder and a spring to bias the vane into engagement with an eccentrically rotatable rotor. The spring is C-shaped and has one end mounted in the vane and the other diametrically located and arranged in the stationary member to pivotally move in response to movement of the vane.

United States Patent [191 Rinehart 7 July 3, 1973 ROTARY COMPRESSOR 3,423,013 1/1969 Rinehart.....'..; 417/4l0 4 X [75] Inventor: Dean C. Rlnehart, Louisville, Ky. 3'532448 long-l0 Rmehan 8 [73] Assignee: General Electric Company, Primary Examiner-Carlton R. Croyle Louisville, Ky. Assistant Examiner-Michael Koczo, Jr. [22] Filed: Jan. 18, 1972 Attorney-Walter E. Rule et al.

[21] App]. No.: 218,721 57 ABSTRACT A rotary Compressor comprising a cylinder, a vane slid- [52] us. Cl. 418/248 bly mo n e in the cylindrical wall of the cylinder and [51] Int. Cl F01c 1/00, F04c' 1/00 a pring to bias th vane into engagement with an ec- [58] Field of Search 418/248 centrically rotatable rotor. The spring is C-shaped and has one end mounted in the vane and the other diamet- [56] References Cited rically located and arranged in the stationary member to pivotally move in response to movement of the vane.

2 Claims, 2 Drawing Figures ROTARY COMPRESSOR BACKGROUND OF THE INVENTION The present invention relates to rotary compressors and is more particularly concerned with the hermetic rotary compressor particularly adapted for use in refrigerating systems and the like.

A well-known type of rotary compressor comprises a cylindrical wall defining a compression cylinder, a rotor eccentrically mounted in the cylinder and a vane slidably mounted on the cylindrical wall for engagement of the inner end thereof with the periphery of the rotor to divide the cylinder into a high-pressure side and a low-pressure side. In the operation of such compressor, it is necessary to maintain the vane in continuous sealing engagement with the rotor surface. For this purpose, there is normally employed one or more compression springs positioned between the outer end of the vane and a suitable, fixed support means. Such spring means have been satisfactory for low displacement rotary compressors in which the maximum distance between the rotor and the cylinder wall is relatively small and during eccentric rotation of the rotor, the vane moves a relatively short distance in maintaining contact with the rotor. However, with higher displacement rotary compressors in which the maximum distance between the eccentric rotor and the cylinder wall is substantial, the vane must move through a longer stroke during each rotation of the rotor. In order to obtain the required biasing action under such conditions, the vane springs must be stiffer and larger, and unless additional space can be provided for these springs, the safe stress limits of the spring may be exceeded with resultant spring breakage.

For instance U.S. Pat. Nos. 3,423,013 and 3,532,448 to D. C. Rinehart are examples of prior art approaches using vane biasing means which did not include the usual compression springs for maintaining the vane in contact with the rotor. Such arrangements are unduly complicated, thus making their initial cost excessive and cuases them to be subject to failure.

A primary object of the present invention is to provide a rotary compressor including improved vane biasing means which is inexpensive, and requires a minimum safe spring force over a large range of compressor displacement.

SUMMARY OF THE INVENTION compressor comprises cylindrical and end walls defining a compression cylinder, a rotor eccentrically rotatable within the cylinder and a radial slot in the cylindrical wall which slidably receives a radial extending vane having an inner end continuously engaging the periphery of the rotor to divide the compression cylinder into a high and low pressure side. The radially projecting portion includes a spring receiving recess having its axis parallel to the compressor axis. The vane is maintained BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIG. 1 is an elevational view partly in cross section of a portion of a hermetic refrigerant compressor incorporating the present invention; and

DESCRIPTION OF THE PREFERRED EMBODIMENT In the accompanying drawing, there is shown a hermetic compressor casing in which there is disposed a rotary compressor unit 11 connected by a drive shaft 12 to an electric motor 13.

The compressor 11 includes a cylindrically shaped housing 14 which is centrally supported in the casing 10 by radially projecting portions or arms 16 and 17 formed on the bottom portion of the housing 14 so as to locate the upper surface 18 approximately at the axial center of the housing 14. Located centrally in the housing 14 is an inner cylindrical wall 19 which in combination with the upper and lower end walls or plates 21 and 22 defines an annular compression or cylinder chamber 23. A rotor 24 driven by an eccentric 25 on the shaft 12 is contained within the chamber 23. A vane 26 slidably disposed within a radial slot 27 is adapted to engage the periphery of rotor 24 and divide the cylinder into a low pressure side 28 and a high pressure side 29. The slot 27 extends through the wall 19 of the housing 14 and into the arm 17 so lhat the lower portion of the vane 26 located beyond the periphery of the housing 14 is supported therein.

Such a hermetic compressor is particularly adapted to be connected to a refrigeration system so as to withdraw low pressure or gaseous refrigerant from the sys tem through a suction line 31 having an outlet port 32 communicating with the low pressure side 28 of the compression chamber through valve 33 and to discharge high pressure refrigerant through a valve controlled discharge port 34 and the interior of the casing 10.

In order to prevent leakage of high pressure refrigerant from the high side 29 to the low side 28 during rotation of the rotor 24 in a counterclockwise direction as viewed in FIG. 2, it is necessary that the forward edge 36 of the vane 26 be maintained in continuous sealing engagement with the periphery of the rotor regardless of the position of the rotating rotor within the chamber 23. This requiresthat during each revolution of the rotor, the vane must reciprocate between a forward position in which the vane extends .into the compression chamber 23 as illustrated in the drawing, and a retracted-position in which the forward edge of the vane is substantially flush with the cylindrical compressor wall 19.

provided an improved means for biasing the vane 26 into engagement with the rotor 24 which does not require the provision of space within the housing structure defining the compressor cylinder, and which does not require the provision of a plunger such as described in the aforementioned US. Pat. No. 3,423,013 Rinehart for assuring the application of longitudinal bi- FIG'. 2 is a sectional view along line 2-2 of FIG. 1.

- In accordance with the present invention, there is d asing forces to the vane, or the spiral spring structure of U.S. Pat. NO. 3,532,448 Rinehart.

More specifically, this means for maintaining the vane 26 in engagement with the rotor 24 comprises a generally C-shaped spring 37, having one end 38 located 180 from the vane 26 and the other end 39 engaged with the outer end of the vane 26 for movement therewith. Located in the portion 16 of the housing 14 diametrically opposite from the vane 26 is a hole or recess 41 extending through the housing '14 and aligned parallel to the axis of shaft 12. Located in the recess 41 is an arm 42 formed on the end 38 of the spring 37. The arm 42 is perpendicular to the spring 37 and extends downwardly from the end 38. Bent radially inwardly from the end 39 of the spring 37 is an arm 43 (FIG. 2) which is received in a recess 44 formed on the outer surface of the vane 26. The portion of spring 37 between ends 38 and 39 is radially spaced from the peripheral wall of housing 14 and lies parallel with an adjacent surface 18 of the arms 16 and 17. Thus, spring 37 is retained in a position to effectively maintain the forward edge of the vane 24 in constant contact with the peripheral surface of the rotor 24 during the operation of the compressor. As seen in FIG. 2, the spring 27 as assembled is arranged perpendicular to the axis of the shaft 12 and in a plane bisecting the compression chamber 23 including the rotor 24 and vane 26. With this arrangement, the force of the spring 37 on the outer edge of the vane 26 is directly on the center of axial dimension of the vane so that equal force is exerted between the outer surface of rotor 24 and the entire contacting inner surface 36 of the vane 26.

In operation, the dimension between the spring ends 38 and 39 changes during each revolution of the rotor 24 as the resulting reciprocating action of the vane 26 causes the spring 37 to stretch as the end 39, carried on the outer edge of the reciprocating vane, is pulled away from the end 38 and its arm 42 located in the recess 41 of the stationary portion 16. As the distance between the recess 41 and the outer surface of the vane 26 changes with each rotation of the rotor 24, the end 38 of the spring 37 is rotated and allowed to pivot about the arm 42 on the surface of the recess 41. This pivoting motion of arm 42 on the surface of recess 41 eliminates any twisting action that would be present in a rigidly held spring. To insure that the spring 37 is maintained in its proper location, as shown in the drawings, a tab portion 45 is bent radially inwardly from the free end of arm 42 and as assembled is located radially inwardly from the hole 41.

In assembling the spring 37 on the compressor, the arm 43 is inserted into the recess 44 and the arm 42 is then placed in the hole 41. it will be noted that to facilitate assembly of the arm 42 in the recess 44, the dimension of the recess 44 is greater than the tab portion 45. By the present invention there is provided a simple and inexpensive vane biasing spring that lends itself to the mass producing and assembling techniques used in present day, manufacturing of rotary compressors.

While in accordance with the patent. statutes there has been described what at present is considered to be the preferred embodiment of the invention,'it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, the aim of the appended claims to cover all such changes and modifications as fall within thetrue spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A hermetic rotary compressor comprising a cylindrical housing having radially extending support arms projecting from the lower axial end portion of the housing for supporting the compressor in a casing, a cylindrical inner wall in the housing and end walls defining a cylinder, a rotor eccentrically rotatable within said cylinder, the housing having a radial slot extending the entire axial dimension of said housing through the cylindrical wall and into a portion of one of the support arms, a vane slidably mounted in the slot for engagement of the inner end with the periphery of the rotor;

the outer end of the vane having an axially extending recess located above the upper surface of said support arms;

the other radially extending arm of the housing having a passage diametrically opposite from the vane and aligned parallel to the axis of the rotor and extending through the arm;

spring means including a C-shaped spring section located in a plane which is perpendicular to the axis of said rotor and which intersects the recess for biasing the vane into engagement with the rotor; a radially inwardly projecting tab at one end of the spring section extending into the recess in the vane;

the other end of the spring section having a portion projecting downwardly perpendicular to the spring section and positioned in the passage in the housmg;

the projecting portion being arranged in the passage to pivotally move in response to movement of said vane during each revolution of the rotor whereby twisting of the spring adjacent the projecting portion is eliminated.

2. The compressor of claim 1 in which the portion of the C-shaped section between its ends is radially spaced from the peripheral wall of the cylindrical housing.

i i i i 

1. A hermetic rotary compressor comprising a cylindrical housing having radially extending support arms projecting from the lower axial end portion of the housing for supporting the compressor in a casing, a cylindrical inner wall in the housing and end walls defining a cylinder, a rotor eccentrically rotatable within said cylinder, the housing having a radial slot extending the entire axial dimension of said housing through the cylindrical wall and into a portion of one of the support arms, a vane slidably mounted in the slot for engagement of the inner end with the periphery of the rotor; the outer end of the vane having an axially extending recess located above the upper surface of said support arms; the other radially extending arm of the housing having a passage diametrically opposite from the vane and aligned parallel to the axis of the rotor and extending throUgh the arm; spring means including a C-shaped spring section located in a plane which is perpendicular to the axis of said rotor and which intersects the recess for biasing the vane into engagement with the rotor; a radially inwardly projecting tab at one end of the spring section extending into the recess in the vane; the other end of the spring section having a portion projecting downwardly perpendicular to the spring section and positioned in the passage in the housing; the projecting portion being arranged in the passage to pivotally move in response to movement of said vane during each revolution of the rotor whereby twisting of the spring adjacent the projecting portion is eliminated.
 2. The compressor of claim 1 in which the portion of the C-shaped section between its ends is radially spaced from the peripheral wall of the cylindrical housing. 